mini-os: work around ld bug causing stupid CTOR count

I'm seeing pvgrub crashing when running CTORs.  It appears its because
the magic in the linker script is generating junk.  If I get ld to
output a map, I see:

.ctors          0x0000000000097000       0x18
                0x0000000000097000                __CTOR_LIST__ = .
                0x0000000000097000        0x4 LONG 0x25c04
                (((__CTOR_END__ - __CTOR_LIST__) / 0x4) - 0x2)
 *(.ctors)
 .ctors         0x0000000000097004       0x10
                /home/jeremy/hg/xen/unstable/stubdom/mini-os-x86_32-grub/mini-os.o
                0x0000000000097014        0x4 LONG 0x0
                0x0000000000097018                __CTOR_END__ = .


In other words, somehow ((0x97018-0x97000) / 4) - 2 = 0x25c04

The specific crash is that the ctor loop tries to call the NULL
sentinel.  I'm seeing the same with the DTOR list.

Avoid this by terminating the loop with the NULL sentinel, and get rid
of the CTOR count entirely.

From: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Keir Fraser <keir@xen.org>

4 files changed, 2 insertions, 8 deletions

diff --git a/extras/mini-os/arch/ia64/minios-ia64.lds b/extras/mini-os/arch/ia64/minios-ia64.lds
index 8b54c0f394..2866a4a644 100644
--- a/extras/mini-os/arch/ia64/minios-ia64.lds
+++ b/extras/mini-os/arch/ia64/minios-ia64.lds
@@ -55,7 +55,6 @@ SECTIONS
   .ctors : AT(ADDR(.ctors) - (((5<<(61))+0x100000000) - (1 << 20)))
 	{
         __CTOR_LIST__ = .;
-        QUAD((__CTOR_END__ - __CTOR_LIST__) / 8 - 2)
         *(.ctors)
 	CONSTRUCTORS
         QUAD(0)
@@ -65,7 +64,6 @@ SECTIONS
   .dtors : AT(ADDR(.dtors) - (((5<<(61))+0x100000000) - (1 << 20)))
         {
         __DTOR_LIST__ = .;
-        QUAD((__DTOR_END__ - __DTOR_LIST__) / 8 - 2)
         *(.dtors)
         QUAD(0)
         __DTOR_END__ = .;
diff --git a/extras/mini-os/arch/x86/minios-x86_32.lds b/extras/mini-os/arch/x86/minios-x86_32.lds
index 13796db768..f5cabb6a11 100644
--- a/extras/mini-os/arch/x86/minios-x86_32.lds
+++ b/extras/mini-os/arch/x86/minios-x86_32.lds
@@ -30,7 +30,6 @@ SECTIONS
 
   .ctors : {
         __CTOR_LIST__ = .;
-        LONG((__CTOR_END__ - __CTOR_LIST__) / 4 - 2)
         *(.ctors)
 	CONSTRUCTORS
         LONG(0)
@@ -39,7 +38,6 @@ SECTIONS
 
   .dtors : {
         __DTOR_LIST__ = .;
-        LONG((__DTOR_END__ - __DTOR_LIST__) / 4 - 2)
         *(.dtors)
         LONG(0)
         __DTOR_END__ = .;
diff --git a/extras/mini-os/arch/x86/minios-x86_64.lds b/extras/mini-os/arch/x86/minios-x86_64.lds
index 6a5c0bb2f9..3da0a9f130 100644
--- a/extras/mini-os/arch/x86/minios-x86_64.lds
+++ b/extras/mini-os/arch/x86/minios-x86_64.lds
@@ -30,7 +30,6 @@ SECTIONS
 
   .ctors : {
         __CTOR_LIST__ = .;
-        QUAD((__CTOR_END__ - __CTOR_LIST__) / 8 - 2)
         *(.ctors)
 	CONSTRUCTORS
         QUAD(0)
@@ -39,7 +38,6 @@ SECTIONS
 
   .dtors : {
         __DTOR_LIST__ = .;
-        QUAD((__DTOR_END__ - __DTOR_LIST__) / 8 - 2)
         *(.dtors)
         QUAD(0)
         __DTOR_END__ = .;
diff --git a/extras/mini-os/main.c b/extras/mini-os/main.c
index 6b53df5e63..b95b889e16 100644
--- a/extras/mini-os/main.c
+++ b/extras/mini-os/main.c
@@ -153,7 +153,7 @@ static void call_main(void *p)
 
     __libc_init_array();
     environ = envp;
-    for (i = 1; i <= __CTOR_LIST__[0]; i++)
+    for (i = 0; __CTOR_LIST__[i] != 0; i++)
         ((void((*)(void)))__CTOR_LIST__[i]) ();
     tzset();
 
@@ -164,7 +164,7 @@ void _exit(int ret)
 {
     int i;
 
-    for (i = 1; i <= __DTOR_LIST__[0]; i++)
+    for (i = 0; __DTOR_LIST__[i] != 0; i++)
         ((void((*)(void)))__DTOR_LIST__[i]) ();
     close_all_files();
     __libc_fini_array();